C&C: Mammoth tank

This mammoth tank remix is printable version of original model which was directly pulled from game files.

Changes:
* Fixed multiple issues that caused slicer missing some objects
* Parts can be printed separately
* Barrel holes are now deeper
* Rocket heads are smoother
* Removed unnecessary parts hovering around.
* Removed stairs because cannot be printed
* Turret can be rotated
* Added soviet star (this isn't soviet version tho)
* Added tank tread wheel details
* Added tank tread